Stacked disk valve trim

Abstract

The present invention provides a cost effective means by which pressure reduction in a fluid flow control device is optimized. The pressure reduction achieved according to the present invention also minimizes valve wear and presents new solutions in reducing, attenuating, eliminating, damping, redirecting, or otherwise defeating valve noise. In accordance with one embodiment of the present invention, a flow control device is provided including a valve trim assembly comprising a plurality of valve trim disks defining a plurality of flow paths along a fluid passage between a fluid inlet and a fluid outlet of the flow control device. Respective flow paths defined by the valve trim disks comprise an expansion/contraction mechanism, a velocity control mechanism, an acoustic chamber, and frequency shifting passages. The expansion/contraction mechanism has a cross section including rapid increases and decreases in cross-sectional flow area. The velocity control mechanism defines a cross-sectional flow profile defining a relatively low cross-sectional flow area proximate the fluid inlet and a relatively high cross-sectional flow area proximate the fluid outlet. The acoustic chamber is configured to defeat acoustic disturbances generated in the expansion/contraction mechanism and the velocity control mechanism. The frequency shifting passages are configured to direct fluid flow from the acoustic chamber to the fluid outlet and increase the sonic frequency of acoustic disturbances associated with the directed fluid.

What is claimed is:  
     
       1. A flow control device including a valve trim assembly comprising a plurality of valve trim disks defining a plurality of flow paths along a fluid passage between a fluid inlet and a fluid outlet of said flow control device, wherein respective flow paths defined by said valve trim disks comprise: 
       an expansion/contraction mechanism having a cross section including rapid increases and decreases in cross-sectional flow area;  
       a velocity control mechanism defining a cross-sectional flow profile defining a relatively low cross-sectional flow area proximate said fluid inlet and a relatively high cross-sectional flow area proximate said fluid outlet;  
       an acoustic chamber configured to defeat acoustic disturbances generated in said expansion/contraction mechanism and said velocity control mechanism; and  
       frequency shifting passages configured to direct fluid flow from said acoustic chamber to said fluid outlet and increase the sonic frequency of acoustic disturbances associated with said directed fluid.  
     
     
       2. A flow control device as claimed in  claim 1  wherein said plurality of valve trim disks includes a plurality of sets of two or more adjacent disks, each of said sets of disks defining a plurality of flow paths extending in a radial direction from a central axis of said set of disks. 
     
     
       3. A flow control device as claimed in  claim 2  wherein said adjacent disks comprise an inlet/outlet disk, a flow passage disk, and a separation disk. 
     
     
       4. A flow control device as claimed in  claim 1  wherein said fluid inlet and said fluid outlet are offset from said flow path along a direction perpendicular to a plane defined by said flow path such that fluid passing from said fluid inlet to said flow path encounters two significant changes in flow direction and fluid passing from said flow path to said fluid outlet encounters two significant changes in flow direction. 
     
     
       5. A flow control device as claimed in  claim 4  wherein fluid passing from said fluid inlet to said flow path encounters two 90 degree changes in flow direction and fluid passing from said flow path to said fluid outlet encounters two 90 degree changes in flow direction. 
     
     
       6. A flow control device as claimed in  claim 5  wherein said fluid inlet is defined along an inner diameter of one of said valve trim disks and said fluid outlet is defined along an outer diameter of one of said valve trim disks. 
     
     
       7. A flow control device as claimed in  claim 1  wherein said plurality of flow paths communicate with said fluid inlet along a pressure equalizing annular ring. 
     
     
       8. A flow control device as claimed in  claim 1  wherein said expansion/contraction mechanism defines a plurality of V-shaped turns defining changes in flow direction of greater than 90 degrees, whereby a fluid passing through one of said turns undergoes rapid expansion going into a turn and rapid contraction coming out of a turn. 
     
     
       9. A flow control device as claimed in  claim 8  wherein said expansion/contraction mechanism defines a plurality of V-shaped turns defining changes in flow direction of greater than 90 degrees and less than 180 degrees. 
     
     
       10. A flow control device as claimed in  claim 9  wherein said V-shaped turns are defined substantially entirely with a single disk of said plurality of disks, lying in a plane defined by said disk. 
     
     
       11. A flow control device as claimed in  claim 1  wherein said expansion/contraction mechanism is defined substantially entirely with a single disk of said plurality of disks, lying in a plane defined by said disk. 
     
     
       12. A flow control device as claimed in  claim 1  wherein said expansion/contraction mechanism defines an average cross sectional area that increases in the direction of said fluid outlet. 
     
     
       13. A flow control device as claimed in  claim 1  wherein said expansion/contraction mechanism directs fluid flow into said acoustic chamber. 
     
     
       14. A flow control device as claimed in  claim 1  wherein said velocity control mechanism and said expansion/contraction mechanism are defined by a common portion of said flow path. 
     
     
       15. A flow control device as claimed in  claim 1  wherein said velocity control mechanism is defined by a portion of said flow passage having an average cross sectional area that increases in the direction of said fluid outlet. 
     
     
       16. A flow control device as claimed in  claim 1  wherein said acoustic chamber is positioned downstream of said expansion/contraction mechanism and said velocity control mechanism. 
     
     
       17. A flow control device as claimed in  claim 1  wherein said acoustic chamber is configured to function as a resonator tuned to at least one frequency corresponding to the frequency of sound generated within said flow passage. 
     
     
       18. A flow control device as claimed in  claim 17  wherein said acoustic chamber is further configured such that said tuned frequency is out of phase with sound entering said acoustic chamber. 
     
     
       19. A flow control device as claimed in  claim 18  wherein said acoustic chamber is further configured such that said tuned frequency is 180 degrees out of phase with sound entering said acoustic chamber. 
     
     
       20. A flow control device as claimed in  claim 1  wherein said acoustic chamber is shaped to minimize creation of standing waves therein. 
     
     
       21. A flow control device as claimed in  claim 1  wherein said acoustic chamber is bounded by non-parallel walls. 
     
     
       22. A flow control device as claimed in  claim 1  wherein said acoustic chamber defines a chamber inlet defined along a chamber wall and wherein said chamber inlet is positioned along said chamber wall such that fluid entering said chamber through said chamber inlet disperses in opposite directions along said chamber wall. 
     
     
       23. A flow control device as claimed in  claim 1  wherein said acoustic chamber defines a chamber inlet and a curved wall opposite said chamber inlet. 
     
     
       24. A flow control device as claimed in  claim 23  wherein said curved wall is configured such that a focal point of said curved wall is offset from a path along which fluid enters said acoustic chamber through said chamber inlet. 
     
     
       25. A flow control device as claimed in  claim 23  wherein said curved wall is configured to minimize redirection of entering fluid back towards said chamber inlet. 
     
     
       26. A flow control device as claimed in  claim 1  wherein said acoustic chamber defines a chamber inlet and a wall opposite said chamber inlet, wherein said wall opposite said chamber inlet is arranged to be angled away from a path along which fluid enters said acoustic chamber through said chamber inlet so as to minimize redirection of entering fluid back towards said chamber inlet. 
     
     
       27. A flow control device as claimed in  claim 1  wherein said frequency shifting passages extend from an outside diameter of a valve trim disk over a portion of said acoustic chamber. 
     
     
       28. A flow control device as claimed in  claim 27  wherein each of said frequency shifting passages extend over said acoustic chamber to a substantially equal extent. 
     
     
       29. A flow control device as claimed in  claim 1  wherein said frequency shifting passages define a cross sectional area that decreases from said acoustic chamber to said fluid outlet. 
     
     
       30. A flow control device as claimed in  claim 1  wherein said frequency shifting passages are configured to isolate outlet streams of adjacent frequency shifting passages, reducing interference between adjacent outlet streams. 
     
     
       31. A flow control device as claimed in  claim 1  wherein said plurality of adjacent disks include a plurality of flow passage disks and wherein each flow passage disk includes expansion/contraction mechanisms, velocity control mechanisms, acoustic chambers, and frequency shifting passages. 
     
     
       32. A flow control device as claimed in  claim 31  wherein each flow passage disk includes cutout portions defining said expansion/contraction mechanisms, velocity control mechanisms, acoustic chambers, and frequency shifting passages, and wherein said cut-out portions extend entirely through the thickness of each flow passage disk. 
     
     
       33. A flow control device including a valve trim assembly comprising a plurality of valve trim disks defining a plurality of flow paths along a fluid passage between a fluid inlet and a fluid outlet of said flow control device, wherein respective flow paths defined by said valve trim disks comprise: 
       an expansion/contraction mechanism having a cross section including rapid increases and decreases in cross-sectional flow area;  
       a velocity control mechanism defining a cross-sectional flow profile defining a relatively low cross-sectional flow area proximate said fluid inlet and a relatively high cross-sectional flow area proximate said fluid outlet; and  
       an acoustic chamber configured to defeat acoustic disturbances generated in said expansion/contraction mechanism and said velocity control mechanism.  
     
     
       34. A flow control device as claimed in  claim 33  further comprising frequency shifting passages configured to direct fluid flow from said acoustic chamber to said fluid outlet and increase the sonic frequency of acoustic disturbances associated with said directed fluid. 
     
     
       35. A flow control device as claimed in  claim 33  wherein said expansion/contraction mechanism defines a plurality of V-shaped turns defining changes in flow direction of greater than 90 degrees, whereby a fluid passing through one of said turns undergoes rapid expansion going into a turn and rapid contraction coming out of a turn. 
     
     
       36. A flow control device including a valve trim assembly comprising a plurality of valve trim disks defining a plurality of flow paths along a fluid passage between a fluid inlet and a fluid outlet of said flow control device, wherein: 
       respective flow paths defined by said valve trim disks comprise an expansion/contraction mechanism having a cross section including rapid increases and decreases in cross-sectional flow area;  
       said expansion/contraction mechanism defines a plurality of V-shaped turns defining changes in flow direction of greater than 90 degrees, whereby a fluid passing through one of said turns undergoes rapid expansion going into a turn and rapid contraction coming out of a turn; and  
       said V-shaped turns are defined substantially entirely with a single disk of said plurality of disks, lying in a plane defined by said disk.  
     
     
       37. A flow control device as claimed in  claim 36  wherein said expansion/contraction mechanism defines an average cross sectional area that increases in the direction of said fluid outlet to define a relatively low cross-sectional flow area proximate said fluid inlet and a relatively high cross-sectional flow area proximate said fluid outlet. 
     
     
       38. A flow control device as claimed in  claim 36  wherein said flow paths defined by said valve trim disks further comprise a velocity control mechanism defining a cross-sectional flow profile defining a relatively low cross-sectional flow area proximate said fluid inlet and a relatively high cross-sectional flow area proximate said fluid outlet. 
     
     
       39. A flow control device as claimed in  claim 36  wherein said flow paths defined by said valve trim disks further comprise an acoustic chamber configured to defeat acoustic disturbances generated in said expansion/contraction mechanism. 
     
     
       40. A flow control device as claimed in  claim 36  wherein said flow paths defined by said valve trim disks further comprise frequency shifting passages configured to direct fluid flow to said fluid outlet and increase the sonic frequency of acoustic disturbances associated with said directed fluid. 
     
     
       41. A flow control device as claimed in  claim 36  wherein said flow paths defined by said valve trim disks further comprise an acoustic chamber configured to defeat acoustic disturbances generated in said expansion/contraction mechanism and said velocity control mechanism and wherein said flow paths defined by said valve trim disks further comprise frequency shifting passages configured to direct fluid flow from said acoustic chamber to said fluid outlet and increase the sonic frequency of acoustic disturbances associated with said directed fluid. 
     
     
       42. A flow control device defining a plurality of flow paths along a fluid passage between a fluid inlet and a fluid outlet of said flow control device, wherein said flow paths comprise: 
       an expansion/contraction mechanism having a cross section including rapid increases and decreases in cross-sectional flow area,  
       a velocity control mechanism defining a cross-sectional flow profile defining a relatively low cross-sectional flow area proximate said fluid inlet and a relatively high cross-sectional flow area proximate said fluid outlet,  
       an acoustic chamber configured to defeat acoustic disturbances generated in said expansion/contraction mechanism and said velocity control mechanism, and  
       frequency shifting passages configured to direct fluid flow from said acoustic chamber to said fluid outlet and increase the sonic frequency of acoustic disturbances associated with said directed fluid.  
     
     
       43. A valve trim disk defining an inside diameter, an outside diameter, and a plurality of flow paths generally directed from said inside diameter to said outside diameter, said flow paths comprising: 
       an expansion/contraction mechanism having a cross section including rapid increases and decreases in cross-sectional flow area, wherein said expansion/contraction mechanism defines a plurality of V-shaped turns defining changes in flow direction of greater than 90 degrees, whereby a fluid passing through one of said turns undergoes rapid expansion going into a turn and rapid contraction coming out of a turn;  
       a velocity control mechanism defining a cross-sectional flow profile defining a relatively low cross-sectional flow area proximate said inside diameter of said disk and a relatively high cross-sectional flow area proximate said outside diameter of said disk; and  
       an acoustic chamber configured to defeat acoustic disturbances generated in said expansion/contraction mechanism and said velocity control mechanism.  
     
     
       44. A set of valve trim disks defining respective, coaxial inside diameters, outside diameters, and a plurality of flow paths generally directed from said inside diameters to said outside diameters, wherein respective flow paths defined by said valve trim disks comprise: 
       an expansion/contraction mechanism having a cross section including rapid increases and decreases in cross-sectional flow area;  
       a velocity control mechanism defining a cross-sectional flow profile defining a relatively low cross-sectional flow area proximate said inside diameters and a relatively high cross-sectional flow area proximate said outside diameters;  
       an acoustic chamber configured to defeat acoustic disturbances generated in said expansion/contraction mechanism and said velocity control mechanism; and  
       frequency shifting passages configured to direct fluid flow from said acoustic chamber and increase the sonic frequency of acoustic disturbances associated with said directed fluid.  
     
     
       45. A flow control device as claimed in  claim 33  further comprising: 
       frequency shifting passages configured to direct fluid flow from said acoustic chamber to said fluid outlet and increase the sonic frequency of acoustic disturbances associated with said directed fluid; and  
       an expansion/contraction mechanism defining a plurality of V-shaped turns defining changes in flow direction of greater than 90 degrees, whereby a fluid passing through one of said turns undergoes rapid expansion going into a turn and rapid contraction coming out of a turn.